Mobile telephones have traditionally been voice-centric devices with proprietary operating systems handling all communication tasks. The Application Programming Interfaces (APIs) in these devices were not made available to third-party developers. As a consequence, end users were dependent on the device manufacturers for applications.
Today, the mobile communications industry is increasingly becoming aware of the importance and benefits of open application environments for mobile devices. Basically, an open application environment permits the installation of third party applications on the mobile device during device manufacture or later on by a user operating the device. Such third party applications may include games, software upgrades, etc.
A. Ghosh et al., “Open application environments in mobile devices: Focus on JME and Ericsson Mobile Platform modules”, Ericsson Review No. 2, Vol. 82, 2005, pages 82 to 91 (ISSN: 0014-0171) describe an exemplary open application environment for mobile devices. The open application environment is based on a mobile platform module with a digital baseband processor supporting one or more RATs such as General Packet Radio Service (GPRS), Enhanced Data for GSM Evolution (EDGE) or Wideband Code-Division Multiple Access (WCDMA). The mobile platform module is an environment that includes all the necessary integrated circuits and software needed to provide wireless network access services and communication services (e.g. for voice, data or multimedia applications), as well as interfaces to make these services available to applications residing within or logically on top of the mobile platform module.
Conventionally, mobile platform modules often included proprietary Operating Systems (OS). Now, with the advent of the open application environment, an application platform module with a third-party application processor will be added to the mobile device when it is desired to run an open OS such as Symbian. The application platform module will be co-located with the mobile platform module in the mobile device and handle applications including, for example, multimedia applications. The mobile platform module, on the other hand, will be in charge of a reduced set of functionalities (including all mobile communication tasks such as providing wireless network access) and mainly act as a network access platform module. Between the application platform module and the mobile platform module an interface mechanism provides the applications on the application platform module with access to platform module-internal functionalities of the mobile platform module as if the applications resided directly on or within the mobile platform module.
As wireless access points supporting different kinds of RATs are becoming ubiquitous, it is only a logical consequence that many mobile platform modules will provide support for more than one RAT. From the perspective of modularity it is sometimes desirable to co-locate in one mobile device two or more platform modules each supporting a different RAT. Such a modular approach facilitates re-using a mobile platform module either in a stand-alone configuration or in any combination with other mobile platform modules.
WO-A-00/22857 teaches a modular approach in which different network access modules (such as a Local Area Network (LAN) module and a Global System for Mobile communications (GSM) module) are interconnected via a communication bus according to the Universal Serial Bus (USB) standard. Other modules connected to the communication bus such as a Closed-Circuit Television (CCTV) module may then selectively transmit signals via the LAN module on the one hand or via the GSM module on the other.
Mobile platform modules are often incorporated in devices with modem functionalities (such as network cards) that provide wireless network access to terminal devices (such as personal computers or laptops). The modem devices may support two or more different RATs to ensure the availability of network access in various environments. Due to modularity considerations, two or more different mobile platform modules may therefore concurrently be installed within the modem device.